Debt Obligations (Details) (USD $)			9 Months Ended	12 Months Ended	1 Months Ended	9 Months Ended	12 Months Ended			9 Months Ended	12 Months Ended	1 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Bank Borrowings	Dec. 31, 2012 Bank Borrowings	Oct. 31, 2013 Bank Borrowings Subsequent Event	Sep. 30, 2013 Senior unsecured notes	Dec. 31, 2012 Senior unsecured notes	Nov. 04, 2013 Senior unsecured notes Subsequent Event Issuance in 2010	Nov. 04, 2013 Senior unsecured notes Subsequent Event Issuance in 2011	Sep. 30, 2013 Uncommitted Private Shelf Agreement	Dec. 31, 2012 Uncommitted Private Shelf Agreement	Oct. 31, 2013 Amended and restated note purchase and private shelf agreement Subsequent Event Maximum	Oct. 30, 2013 Amended and restated note purchase and private shelf agreement Subsequent Event Maximum	Sep. 30, 2013 Bonds payable property	Sep. 30, 2012 Bonds payable	Dec. 31, 2012 Bonds payable property
Debt Obligations
Maximum availability under Unsecured Credit Agreement			$ 240,000,000	$ 240,000,000
Possible total maximum availability under Unsecured Credit Agreement			350,000,000	350,000,000
Decrease in drawn pricing, basis point (as a percent)			0.25%	0.25%
Decrease in undrawn pricing, basis point (as a percent)			0.10%	0.10%
Additional extension period option				1 year
Extension of maturity date				1 year
Description of interest rate			LIBOR
Basis spread over base rate (as a percent)			1.25%
Unused commitment fee (as a percent)			0.25%
Amount borrowed			2,000,000		86,000,000
Repayment amount			117,500,000
Amount outstanding under Unsecured Credit Agreement		115,500,000	0		86,000,000			50,000,000	50,000,000
Amount outstanding Senior Unsecured Notes	185,800,000	185,800,000				185,800,000	185,800,000
Weighted average interest rate (as a percent)						5.20%	5.20%							2.90%
Maximum available for issuance under private shelf agreement										100,000,000	100,000,000
Final maturity												12 years
Average life from the date of original issuance												10 years
Debt Instrument Covenant Aggregate Indebtedness As A Percentage of Aggregate Asset													50.00%
Debt Instrument Covenant Unsecured Debt As A Percentage of Unencumbered Asset Pool													60.00%
Amount outstanding														2,035,000		2,635,000
Number of assisted living properties securing debt instruments														5		5
Repayments of debt														600,000	565,000
Aggregate carrying value of real estate property securing the entity's debt obligation														6,452,000		6,650,000
Amount available for borrowing under Unsecured Credit Agreement					$ 154,000,000